Vinnie,

It has been my experience in the past that over time the slides do lose
their charge.  However, it is easy enough to check for that:  if you
submerge your slide in your adhesive-free waterbath and the water beads
up on the slide, there is still a charge left.  If it doesn't, you can
be pretty sure the sections will come off the slides, particularly if
using heat and/or enzyme antigen retrieval.  When I open a new box of
slides, I always random check at least two or three slides to make sure
they are still charged.

Hermina

Vinnie Della Speranza wrote:

>  John, something I've wondered about and would appreciate your
> thoughts. what assurance does anyone have that these slides remain
> charged over time?I would think that those amino groups want to
> attract anything that will neutralize their charge and couldn't this
> happen long before that tissue section ends up on the slide?    Vinnie
> Della Speranza
> Manager for Anatomic Pathology Services
> Medical University of South Carolina
> 165 Ashley Avenue  Suite 309
> Charleston, SC 29425
> Ph: 843-792-6353
> fax: 843-792-8974
>
> >>> "J. A. Kiernan"  05/29/02 03:06PM >>>
> rueggp wrote:
> >
> > are APES coated slides available for sale already prepared or do you
>
> > have to coat them yourself in house.
>
> APES (aminopropyltriethoxysilane) does not coat the slide;
> it reacts chemically with the silicate of the glass.
> The treatment with APES chemically binds amino groups to the
> surface of the glass, which consequently becomes positively
> charged when wetted with water.
>
> Positively charged slides are sold ready-made under
> various trade names. I don't know if they are made with
> APES or with some other ethoxysilane that has a basic
> side-chain.
>
> --
> -------------------------
> John A. Kiernan
> Department of Anatomy and Cell Biology
> The University of Western Ontario
> London,   Canada   N6A 5C1
>    kiernan@uwo.ca
>    http://publish.uwo.ca/~jkiernan/
>
>

--
Hermina M. Borgerink, BA, HTL(ASCP)HT, IHQ
Department of Pathology
Wake Forest University School of Medicine
Winston-Salem, N.C. 27157
PH (336) 716-1538
Fax (336) 716-1515